Barcelona take a commanding 3-1 aggregate lead into their UEFA Champions League second-leg tie against Bayer Leverkusen at Camp Nou on Wednesday evening.

Barca were particularly impressive at the Bay Arena three weeks ago and were superior to their German opponents in every department.

Leverkusen manager Robin Dutt knows that he faces a tough task to help his team progress. If they are to force an upset, every member of the starting 11 will have to put in a serious shift.

Here I take a look at six key battles that could have a major impact on the fixture.

Lionel Messi vs. Michal Kadlec

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Michael Kadlec worked hard for his team and scored a very good header in the first leg. Defensively, Kadlec struggled to deal with the pace of Adriano and particularly the class of Lionel Messi.

Kadlec is not the first player to be unable to deal with the gifted Argentine, nor will he be the last. Nevertheless, on any other day, Barcelona's dominance could have led to double figures.

Kadlec must find a way to minimize Messi's impact at Camp Nou. This will undoubtedly require some luck.

I just can't help but feel that if Messi turns up, Kadlec may have an even tougher time than he did in the first leg.

Eric Abidal vs. Renato Augusto and Vedran Corluka

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Eric Abidal had to deal with both Renato Augusto and Vedran Corluka on his side of the pitch at the Bay Arena.

While the Frenchman offered good support to his teammates when he pushed forward, he will have been disappointed with the way Corluka was able to get to the byline and cross for Kadlec's goal.

Augusto showed he has some class to him and could have scored on the night. The key for Bayer will be to exploit Abidal's tendency to move forward. If Augusto and Corluka combine quickly and effectively, they may have a chance to exploit the space in the Barcelona defence.

Adriano vs. Vedran Corluka

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It looks like Vedran Corluka may have a lot to do in this match.

The Croatian did well to restrict Adriano's influence in the first match and he will need to put in a similar shift if his side is to have any chance of progression.

The Brazilian attacked positively for Barcelona and always looked a threat when on the ball.

This was probably the most evenly matched battle in the first leg. It will be interesting to see who prevails in this individual matchup at Camp Nou.

Pedro vs. Daniel Schwaab

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Alexis Sanchez was vastly influential in Germany and instrumental in the majority of Barca's attacks.

The Chilean will be missing from this tie and is likely to be replaced by Pedro.

Sanchez exploited Daniel Schwaab on several occasions. While the German will be relieved to avoid Sanchez, the sight of Pedro running at him will not relax the defender.

Pedro is just returning from injury, but he is a fantastic player when on song. Schwaab should be aware that the Spaniard is due to return to form and it could happen tomorrow night.

Barcelona Attack vs. Bernd Leno

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Leno was not to blame for anything that happened in the first leg.

Despite Barca's dominance, Leno had very little to do and was always composed in the Leverkusen goal.

There is no tougher test for a young goalkeeper than visiting Barcelona, so he will need to stay alert and produce the performance of a lifetime for his team.

He has a lot of responsibility at such a young age, but could have a crucial say in the outcome of this match.

Cesc Fabregas vs. Lars Bender

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Lars Bender will need to have a good match at the Camp Nou. He worked desperately hard at the Bay Arena and was constantly looking to give his back four extra protection.

Bender is not only a brilliant defensive midfielder, but also a good passer; he will need to find his range to set the attackers off.

Cesc Fabregas will look to push forward as much as possible. Bender will have a tough task to prevent the Spaniard from influencing the game.